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Atomic Weight of Chromium | Commission on Isotopic Abundances and Atomic Weights
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"><head> <title>Atomic Weight of Chromium | Commission on Isotopic Abundances and Atomic Weights</title> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> <link rel="stylesheet" type="text/css" media="all" href="stylesheet.css"><link rel="shortcut icon" href="favicon.ico" /> <link href="css/theme.blue.css" rel="stylesheet" type="text/css"/> <script type="text/javascript" src="js/jquery-1.11.1.min.js"></script> <script type="text/javascript" src="js/jquery.tablesorter.js"></script> <script type="text/javascript" src="js/jquery.tablesorter.min.js"></script> <script type="text/javascript" src="js/jquery.tablesorter.widgets.js"></script> <script language="JavaScript" type="text/javascript"> $(function() { $("#mytable").tablesorter({theme:'blue',headers:{3:{sorter:'brace'},4:{sorter:false}},widgets:['zebra'],widthFixed:true}); }); </script> <script type="text/javascript"> var _gaq = _gaq || []; _gaq.push(['_setAccount', 'UA-37565923-4']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); </script> </head> <body> <div id="pagewidth"> <div id="header-top" class="clearfix"> <!-- support-navigation start --> <div id="support-navigation"> <ul></ul> </div> <!-- support-navigation end --> <!-- logo start --> <div id="logo-top"> <a href="http://www.ciaaw.org"><img src="images/ciaaw.png" alt="Logo of the Atomic Weights Commission"></a> <a href="http://www.iupac.org" target="_blank"><img src="images/iupac.png" class="xx" alt="Logo of the International Union of Pure and Applied Chemistry"></a> </div> <!-- logo end --> <!-- main-navigation start --> <div id="main-navigation"> <ul> <li><a href="index.htm">Home</a></li> <li><a href="atomic-weights.htm">Atomic Weights</a></li> <li><a href="isotopic-abundances.htm">Isotopic Abundances</a></li> <li><a href="reference-materials.htm">Reference Materials</a></li> <li><a href="commission.htm">The Commission</a></li> <li><a href="info.htm">FAQ's</a></li> </ul> </div> <!-- main-navigation end --> </div id="header-top"> <!-- header-top end --> <div id="breadcrumb"> <ul> <li><a href="index.htm">Other elements</a></li> </ul></div> <div id="content"> <div id="main-content"> <h1>Chromium</h1><p><table id="mytable" class="tablesorter"><thead><tr><th>Isotope</th><th>Atomic mass (Da)</th><th>Isotopic abundance (amount fraction)</th></tr></thead> <tbody> <tr><td><sup>50</sup>Cr </td><td>49.946 041(3)</td><td>0.043 45(13)</td></tr> <tr><td><sup>52</sup>Cr </td><td>51.940 505(3)</td><td>0.837 89(18)</td></tr> <tr><td><sup>53</sup>Cr </td><td>52.940 647(3)</td><td>0.095 01(17)</td></tr> <tr><td><sup>54</sup>Cr </td><td>53.938 878(3)</td><td>0.023 65(7)</td></tr> </tbody></table><br> <p> In 1983 the Commission recommended the standard atomic weight of chromium to four decimal places, <i>A</i><sub>r</sub>(Cr) = 51.9961(6). Meanwhile, report isotope fractionation of chromium during chromate reduction, resulting in <i>δ</i><sup>53</sup>Cr<sub>SRM979</sub> values in groundwater samples as high as +5.8 ‰ or <i>A</i><sub>r</sub>(Cr) = 51.9982, which is outside the current range of uncertainty of the standard atomic weight. Measurements of <i>n</i>(<sup>53</sup>Cr)/<i>n</i>(<sup>52</sup>Cr) can be expressed as <i>δ</i><sup>53</sup>Cr values with respect to NIST SRM 979. </p> <h9><font color=red>SOURCE</font> <a href="publications.htm#P3">Atomic weights of the elements: Review 2000</a> by John R de Laeter et al. <i>Pure Appl. Chem.</i> 2003 (75) 683-800<br>© IUPAC 2003</h9> </div> <!-- support-content start--> <div id="support-content"> <img src="images/p-table/Cr.png"><p class="credit">CIAAW</p> <p class="caption"><strong>Chromium</strong><br> <i>A</i><sub>r</sub>(Cr) = 51.9961(6) since 1983<br><br> The name derives from the Greek <i>chroma</i> for "colour", from the many coloured compounds of chromium. It was discovered in 1797 by the French chemist and pharmacist Nicolas-Louis Vauquelin, who also isolated chromium in 1798. <br> <p class="caption"><a href="chromium-references.htm">Isotopic reference materials</a> of chromium.</p> </div id="support-content"> <!-- support-content end--> </div id="content"> <!-- content end--> <div id="push"></div></div id="pagewidth"> <!-- footer start --> <div id="footer"> <img src="images/logo.png"><br><br> <a href="privacy.htm">Privacy policy</a> | <a href="impressum.htm">Impressum</a> | <a href="members.htm">Contact</a> | © CIAAW, 2007-2015 <br> </div> <!-- footer end --> </body></html>